A speculum is a medical instrument for dilating the opening of a body cavity for medical examination. A vaginal speculum commonly used during a gynecological examination or a surgical procedure is introduced into a patient's vagina to separate the vaginal walls, thus allowing the internal genital organs to be examined. Metal, autoclavable specula are conventionally used for gynecological examination and treatment. These units, with exposed joints, sharp edges, and cold metal are universally disliked by patients. The hinged joints and blade edges often pinch, scrape, or otherwise traumatize the supporting tissues in the area being examined. The conventional metallic specula blades are typically opaque. Therefore, the only area available for inspection when a metallic speculum is in use is the open end, for cervical examination, and the vaginal wall areas between the blades.
In an attempt to eliminate some of the problems mentioned above, plastic specula have been developed. Plastic specula, which are formed from plastic or another lightweight and inexpensive material, are often designed with a double-hinge. Although these double-hinge designs satisfactorily support the vertical stresses placed on the speculum, current designs allow for significant movement when exposed to lateral forces. Such lateral forces are common when vaginal muscles become tense during procedures which do not require anesthesia, and the resulting lateral movement is objectional to the physician because it can result in speculum movement inside the vagina, or in the worst case speculum collapse.
Sufficient lighting of the subject area for examination is another area of difficulty, since typical specula are not equipped with illumination devices. Light must be directed from another source, often a gooseneck lamp that can partially obstruct the view into the vagina. Head-mounted lights have been used as a partial solution to this problem, but such head-mounted lights are uncomfortable for the operator and cumbersome due to the light cord. Lights built into the handle of existing specula generally project into a light pipe which follows up the center of the speculum. Since this light and light pipe assembly occupy the center of the handle the speculum hinge mechanism must be offset to one side. However, such offsetting from the center of the speculum has the undesirable effect of increasing lateral movement resulting from stress.